417 results
Search Results
402. On the gap between prime ideals
- Author
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Tianyu Ni
- Subjects
ring of integers ,Pure mathematics ,diophantine equations ,quadratic field ,General Mathematics ,Diophantine equation ,Mathematics::Number Theory ,lcsh:Mathematics ,Algebraic number field ,Cyclotomic field ,lcsh:QA1-939 ,Ring of integers ,Measure (mathematics) ,Prime (order theory) ,cyclotomic field ,Prime gap ,Quadratic field ,prime gap ,Mathematics - Abstract
We define a gap function to measure the difference of two distinct prime ideals in a given number field. In this paper, we determine all quadratic fields and cyclotomic fields satisfying the condition: there exist two distinct prime ideals whose gap is 1.
- Published
- 2019
403. Some new inequalities of the Grüss type for conformable fractional integrals
- Author
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Kottakkaran Sooppy Nisar, Feng Qi, and Gauhar Rahman
- Subjects
Mathematics::Functional Analysis ,Pure mathematics ,General Mathematics ,lcsh:Mathematics ,010102 general mathematics ,Mathematics::Classical Analysis and ODEs ,Conformable matrix ,Type (model theory) ,lcsh:QA1-939 ,01 natural sciences ,Riemann–Liouville fractional integral| inequality of the Grüss type| conformable fractional integral| integral inequality| fractional integral operator ,010101 applied mathematics ,0101 mathematics ,Mathematics - Abstract
In the paper, the authors establish some new inequalities of the Gruss type for conformable fractional integrals. These inequalities generalize some known results.
- Published
- 2018
404. Lower bounds for the blow-up time to a nonlinear viscoelastic wave equation with strong damping
- Author
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Yadong Shang, Xiaoxiao Zheng, and Xiaoming Peng
- Subjects
Physics ,Work (thermodynamics) ,General Mathematics ,Applied Mathematics ,lcsh:Mathematics ,010102 general mathematics ,Mathematical analysis ,Function (mathematics) ,Wave equation ,First order ,lcsh:QA1-939 ,01 natural sciences ,Upper and lower bounds ,Viscoelasticity ,010101 applied mathematics ,Nonlinear system ,Relaxation (physics) ,lower bound| blow up| viscoelastic| strong damping| memory ,0101 mathematics ,Differential inequalities ,Interpolation ,Mathematics - Abstract
This paper deals with a nonlinear viscoelastic wave equation with strong damping. By the means of the interpolation inequalities and di erential inequality technique, we obtain a lower bound for blow-up time of the solution. This result extends our earlier work Peng et al. [Appl. Math. Lett., 76, 2018].
- Published
- 2018
405. Smoking dynamics with health education effect
- Author
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Zeyu Zhang, Xianbo Sun, and Pengcheng Xiao
- Subjects
Lyapunov function ,education.field_of_study ,General Mathematics ,lcsh:Mathematics ,010102 general mathematics ,Population ,Dynamics (mechanics) ,smoking dynamics| mathematical modeling| health education| equilibrium| stability| Lyapunov function ,lcsh:QA1-939 ,01 natural sciences ,Stability (probability) ,03 medical and health sciences ,symbols.namesake ,Next-generation matrix ,0302 clinical medicine ,Stability theory ,symbols ,Applied mathematics ,Health education ,030212 general & internal medicine ,0101 mathematics ,education ,Basic reproduction number ,Mathematics - Abstract
This paper provides a mathematical study for analyzing the dynamics of smoking with health education campaigns involved. The method of next generation matrix is used to derive the basic reproduction number $R_0$. We prove that the smoking-free equilibrium is both locally and globally asymptotically stable if $R_0 < 1$; and the smoking-present equilibrium is globally asymptotically stable if $R_0 > 1$. By comparing with smoking dynamics without health education involved, we conclude that health education can decrease smoking population. Numerical simulations are used to support our conclusions.
- Published
- 2018
406. Dynamics analysis of stochastic tuberculosis model transmission withimmune response
- Author
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Texance Mbaya and Jean Luc Dimi
- Subjects
Transmission (telecommunications) ,General Mathematics ,lcsh:Mathematics ,Applied mathematics ,Quantitative Biology::Populations and Evolution ,Epidemic model ,lcsh:QA1-939 ,Quantitative Biology::Other ,nonlinear epidemic model| Lyapounov function| stochastic asymptotic stability ,Itô’sformula ,Mathematics - Abstract
In this paper we extend the tuberculosis epidemic model from a deterministic frameworkto a deterministic model with immunue response and after to stochastic one. We formulate it asa stochastic di erential equation. We, then, etablish the stabilities of di erent equilibria, and giveconditions for extinction and persistence of the desease.
- Published
- 2018
407. Study of Multivalent Spirallike Bazilevic Functions
- Author
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Nazar Khan, Bilal Khan, Qazi Zahoor Ahmad, Ajmal Khan, and Shahid Khan
- Subjects
Pure mathematics ,Mathematics::Complex Variables ,General Mathematics ,lcsh:Mathematics ,kpirallike function| Bazilevic functions| multivalent function| necessary and su cientconditions ,lcsh:QA1-939 ,Convexity ,Mathematics - Abstract
In this paper, we introduce certain new subclasses of multivalent spirallike Bazilevicfunctions by using the concept of k-uniformly starlikness and k-uniformly convexity. We proveinclusion relations, su cient condition and Fekete-Szego inequality for these classes of functions.Convolution properties for these classes are also discussed.
- Published
- 2018
408. On global well-posedness and decay of 3D Ericksen-Leslie system
- Author
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Xiufang Zhao and Ning Duan
- Subjects
Physics ,ericksen-leslie system ,Cauchy stress tensor ,General Mathematics ,Time decay ,Mathematics::Analysis of PDEs ,Type (model theory) ,global well-posedness ,decay ,Strong solutions ,QA1-939 ,Initial value problem ,strong solutions ,Well posedness ,Mathematics ,Mathematical physics - Abstract
In this paper, the small initial data global well-posedness and time decay estimates of strong solutions to the Cauchy problem of 3D incompressible liquid crystal system with general Leslie stress tensor are studied. First, assuming that $ \|u_0\|_{\dot{H}^{\frac12+\varepsilon}}+\|d_0-d_*\|_{\dot{H}^{\frac32+\varepsilon}} $ ($ \varepsilon > 0) $ is sufficiently small, we obtain the global well-posedness of strong solutions. Moreover, the $ L^p $–$ L^2 $ ($ \frac32\leq p\leq2 $) type optimal decay rates of the higher-order spatial derivatives of solutions are also obtained. The $ \dot{H}^{-s} $ ($ 0\leq s < \frac12 $) negative Sobolev norms are shown to be preserved along time evolution and enhance the decay rates.
- Published
- 2021
409. A SOR-like AVM for the maximal correlation problem
- Author
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Jun He
- Subjects
TheoryofComputation_MISCELLANEOUS ,Multivariate statistics ,General Mathematics ,lcsh:Mathematics ,lcsh:QA1-939 ,Computer Science::Numerical Analysis ,Variable (computer science) ,Maximal correlation ,Monotone polygon ,Power iteration ,Convergence (routing) ,Applied mathematics ,multivariate statistics| maximal correlation problem convergence| multivariateeigenvalue problem| global maximizer| power method ,Mathematics - Abstract
In this paper, a SOR-like alternating variable method for computing the global solution of the maximal correlation problem is presented. The monotone convergence of the SOR-like alternating variable method is proved. Numerical experiments show the effciency of our method.
- Published
- 2018
410. A note on derivations and Jordan ideals of prime rings
- Author
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Gurninder S. Sandhu and Deepak Kumar
- Subjects
Associated prime ,Pure mathematics ,Prime rings| Jordan ideals| Generalized derivations| Martindale ring of quotients|Generalized polynomial identities (GPIs) ,General Mathematics ,lcsh:Mathematics ,Prime ring ,Semiprime ring ,Minimal ideal ,Ideal (ring theory) ,lcsh:QA1-939 ,Commutative property ,Prime (order theory) ,Mathematics - Abstract
Let F : R → R be a generalized derivation of a 2-torsion free prime ring R together witha derivation d: In this paper, we show that a nonzero Jordan ideal J of R contains a nonzero ideal ofR. Further, we use this result to prove that if F([x,y]) ∈ Z(R) for all x, y ∈ J; then R is commutative.Consequently, it extends a result of Oukhtite, Mamouni and Ashraf.
- Published
- 2017
411. Localized Orthogonal Decomposition for two-scale Helmholtz-typeproblems
- Author
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Barbara Verfürth and Mario Ohlberger
- Subjects
Helmholtz equation ,Function space ,General Mathematics ,Geometry ,010103 numerical & computational mathematics ,01 natural sciences ,Homogenization (chemistry) ,symbols.namesake ,FOS: Mathematics ,Multiscale method| pollution e ect| Helmholtz equation| finite elements| numericalhomogenization ,Oversampling ,Periodic boundary conditions ,Mathematics - Numerical Analysis ,ddc:510 ,0101 mathematics ,Mathematics ,35J05, 35B27, 65N12, 65N15, 65N30, 78M40 ,lcsh:Mathematics ,Mathematical analysis ,Numerical Analysis (math.NA) ,lcsh:QA1-939 ,Finite element method ,010101 applied mathematics ,Wavelength ,Helmholtz free energy ,symbols - Abstract
In this paper, we present a Localized Orthogonal Decomposition (LOD) in Petrov-Galerkin formulation for a two-scale Helmholtz-type problem. The two-scale problem is, for instance, motivated from the homogenization of the Helmholtz equation with high contrast, studied together with a corresponding multiscale method in (Ohlberger, Verf\"urth. A new Heterogeneous Multiscale Method for the Helmholtz equation with high contrast, arXiv:1605.03400, 2016). There, an unavoidable resolution condition on the mesh sizes in terms of the wave number has been observed, which is known as "pollution effect" in the finite element literature. Following ideas of (Gallistl, Peterseim. Comput. Methods Appl. Mech. Engrg. 295:1-17, 2015), we use standard finite element functions for the trial space, whereas the test functions are enriched by solutions of subscale problems (solved on a finer grid) on local patches. Provided that the oversampling parameter $m$, which indicates the size of the patches, is coupled logarithmically to the wave number, we obtain a quasi-optimal method under a reasonable resolution of a few degrees of freedom per wave length, thus overcoming the pollution effect. In the two-scale setting, the main challenges for the LOD lie in the coupling of the function spaces and in the periodic boundary conditions., Comment: 20 pages
- Published
- 2017
412. A regularity criterion of weak solutions to the 3D Boussinesq equations
- Author
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Sadek Gala, Maria Alessandra Ragusa, and Ahmad Mohammed Alghamdi
- Subjects
Physics ,Pure mathematics ,General Mathematics ,Weak solution ,lcsh:Mathematics ,Mathematical analysis ,Mathematics::Analysis of PDEs ,Regularity criterion| Boussinesq equations| a priori estimates ,lcsh:QA1-939 ,Combinatorics ,Nonlinear system ,Type condition ,Partial derivative ,Besov space ,Nabla symbol ,Mathematics - Abstract
The paper deals with the regularity criteria for the weak solutions to the 3D Boussinesq equations in terms of the partial derivatives in Besov spaces. It is proved that the weak solution $$(u,\theta )$$ becomes regular provided that $$\begin{aligned} (\nabla _{h}{\widetilde{u}},\nabla _{h}\theta )\in L^{1}(0,T;\overset{\cdot }{B }_{\infty ,\infty }^{0}({\mathbb {R}}^{3})) \end{aligned}$$Our results improve and extend the well-known result of Dong and Zhang (Nonlinear Anal 11:2415–2421, 2010) for the Navier–Stokes equations.
- Published
- 2017
413. Logarithmically improved regularity criteria for the Boussinesq equations
- Author
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Sadek Gala, Mohamed Mechdene, and Maria Alessandra Ragusa
- Subjects
General Mathematics ,lcsh:Mathematics ,010102 general mathematics ,Mathematical analysis ,Mathematics::Analysis of PDEs ,A priori estimates ,Regularity criterion ,lcsh:QA1-939 ,01 natural sciences ,010101 applied mathematics ,Combinatorics ,Boussinesq equations ,Besov space ,0101 mathematics ,Regularity criterion| Boussinesq equations| A priori estimates ,Mathematics - Abstract
In this paper, logarithmically improved regularity criteria for the Boussinesq equations are established under the framework of Besov space $\overset{.}{B}_{\infty ,\infty }^{-r}$. We prove the solution $(u,\theta )$ is smooth up to time $T>0$ provided that \begin{equation} \int_{0}^{T}\frac{\left\Vert u(\cdot ,t)\right\Vert _{\overset{.}{B} _{\infty ,\infty }^{-r}}^{\frac{2}{1-r}}}{\log (e+\left\Vert u(t,.)\right\Vert _{\overset{.}{B}_{\infty ,\infty }^{-r}})}dt
- Published
- 2017
414. Approximation of solutions of multi-dimensional linear stochastic differential equations defined by weakly dependent random variables
- Author
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Ken Ichi Yoshihara and Hiroshi Takahashi
- Subjects
Independent equation ,Differential equation ,General Mathematics ,lcsh:Mathematics ,Mathematical analysis ,Malliavin calculus ,lcsh:QA1-939 ,Stochastic partial differential equation ,Examples of differential equations ,symbols.namesake ,Stochastic differential equation ,Nonlinear system ,Runge–Kutta method ,symbols ,Difference equation| weakly dependent random variables| Euler-Maruyama scheme| strong invariance principle| linear stochastic di erential equation ,Mathematics - Abstract
It is well-known that under suitable conditions there exists a unique solution of a ddimensional linear stochastic differential equation. The explicit expression of the solution, however, is not given in general. Hence, numerical methods to obtain approximate solutions are useful for such stochastic di erential equations. In this paper, we consider stochastic difference equations corresponding to linear stochastic differential equations. The difference equations are constructed by weakly dependent random variables, and this formulation is raised by the view points of time series. We show a convergence theorem on the stochastic difference equations.
- Published
- 2017
415. A note on the inclusion sets for singular values
- Author
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Jun He, Yan-Min Liu, Ze-Rong Ren, and Jun-Kang Tian
- Subjects
Discrete mathematics ,Singular value ,Matrix (mathematics) ,Computer Science::Discrete Mathematics ,General Mathematics ,lcsh:Mathematics ,Singular value| Matrix| Inclusion sets ,lcsh:QA1-939 ,Mathematics - Abstract
In this paper, for a given matrix $A=(a_{ij}) \in \mathbb{C}^{n\times n}$, in terms of $r_i$ and $c_i$, where $ r_i = \sum\limits_{j = 1,j \ne i}^n {\left| {a_{ij} } \right|}, \ \ c_i = \sum\limits_{j = 1,j \ne i}^n {\left| {a_{ji} } \right|} $, some new inclusion sets for singular values of a matrix are established. It is proved that the new inclusion sets are tighter than the Gersgorin-type sets [1] and the Brauer-type sets [2]. A numerical experiment show the efficiency of our new results.
- Published
- 2017
416. Some Convolution Properties of Multivalent Analytic Functions
- Author
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Sarfraz Ahmad, Qazi Zahoor Ahmad, Bilal Khan, and Nazar Khan
- Subjects
Discrete mathematics ,Pure mathematics ,General Mathematics ,lcsh:Mathematics ,lcsh:QA1-939 ,Unit disk ,Subclass ,Domain (mathematical analysis) ,Convolution ,Multivalent functions| Hadamard product| Conic domain| Analytic functions| Suffcient condition ,Conic section ,Hadamard product ,Analytic function ,Mathematics - Abstract
In this paper, we introduce a new subclass of multivalent functions associated with conic domain in an open unit disk. We study some convolution properties, su cient condition for the functions belonging to this new class.
- Published
- 2017
417. A logarithmically improved regularity criterion for the 3D MHD equations in Morrey-Campanato space
- Author
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Sadek Gala and Maria Alessandra Ragusa
- Subjects
Pure mathematics ,Logarithm ,Morrey–Campanato space ,MHD equations| regularity criteria ,General Mathematics ,lcsh:Mathematics ,Mathematical analysis ,Mathematics::Analysis of PDEs ,Derivative ,lcsh:QA1-939 ,Type condition ,Partial derivative ,Magnetohydrodynamics ,Mathematics - Abstract
In this paper, we will establish a sufficient condition for the regularity criterion to the 3D MHD equation in terms of the derivative of the pressure in one direction. It is shown that if the partial derivative of the pressure $\partial _{3}\pi $ satisfies the logarithmical Serrin type condition $\partial _{3}\pi $ satisfies the logarithmical Serrin type condition \begin{equation*} \int_{0}^{T}\frac{\left\Vert \partial _{3}\pi (s)\right\Vert _{\overset{% \cdot }{\mathcal{M}}_{2,\frac{3}{r}}}^{\frac{2}{2-r}}}{1+\ln (1+\left\Vert b(s)\right\Vert _{L^{4}})}ds
- Published
- 2016
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